Color output in console

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This page was created to consolidate colorization of CLI outputs.

1 Applications

1.1 diff

diffutils from version 3.4 includes the --color option (GNU mailing list).

$ alias diff='diff --color=auto'

1.2 grep

The --color=auto option enables color highlighting. Color codes are emitted only on standard output; not in pipes or redirection.

Color output in grep is also useful with regexp tasks.

Use an alias to permanently enable this option:

alias grep='grep --color=auto'

The GREP_COLORS variable is used to define colors, and it configures various parts of highlighting.

See grep(1) for more information.

This article or section is out of date.

Please help improve the wiki by updating the article and correcting mistakes.

The GREP_COLOR environment variable can be used to define the default highlight color (the default is red). To change the color, find the needed ANSI escape sequence and apply it with:

export GREP_COLOR="1;32"

The -n option includes file line numbers in the output.

1.3 less

1.3.1 Environment variables

Add the following lines to your shell configuration file:

export LESS=-R
export LESS_TERMCAP_mb=$'\E[1;31m'     # begin bold
export LESS_TERMCAP_md=$'\E[1;36m'     # begin blink
export LESS_TERMCAP_me=$'\E[0m'        # reset bold/blink
export LESS_TERMCAP_so=$'\E[01;44;33m' # begin reverse video
export LESS_TERMCAP_se=$'\E[0m'        # reset reverse video
export LESS_TERMCAP_us=$'\E[1;32m'     # begin underline
export LESS_TERMCAP_ue=$'\E[0m'        # reset underline
# and so on

Change the values (ANSI escape code) as you like. This blog post and the page Bash/Prompt customization also help.

Note: The LESS_TERMCAP_xx variables are currently undocumented in less(1). For a detailed explanation, see this answer.

1.3.2 Reading from stdin

Note: It is recommended to add colored output through #Environment variables to your ~/.bashrc or ~/.zshrc, as the below is based on export LESS=R

When you run a command and pipe its standard output (stdout) to less for a paged view (e.g. pacman -Qe | less), you may find that the output is no longer colored. This is usually because the program tries to detect if its stdout is an interactive terminal, in which case it prints colored text, and otherwise prints uncolored text. This is good behaviour when you want to redirect stdout to a file, e.g. pacman -Qe > pkglst-backup.txt, but less suited when you want to view output in less.

Some programs provide an option to disable the interactive tty detection:

# dmesg --color=always | less

In case that the program does not provide any similar option, it is possible to trick the program into thinking its stdout is an interactive terminal with the following utility:

unbuffer — A tclsh script comes with expect, it invokes desired program within a pty.

http://expect.sourceforge.net/example/unbuffer.man.html || expect

Example: unbuffer program | less

Alternatively, using zpty module from zsh: [1]

~/.zshrc

zmodload zsh/zpty

pty() {
	zpty pty-${UID} ${1+$@}
	if [[ ! -t 1 ]];then
		setopt local_traps
		trap '' INT
	fi
	zpty -r pty-${UID}
	zpty -d pty-${UID}
}

ptyless() {
	pty $@ | less
}

Usage:

$ ptyless program

To pipe it to other pager (less in this example):

$ pty program | less

1.4 ls

The --color=auto option enables color highlighting. Color codes are emitted only on standard output; not in pipes or redirection.

Use an alias to permanently enable this option:

alias ls='ls --color=auto'

The LS_COLORS variable is used to define colors, and it configures various parts of highlighting. Use the dircolors(1) command to set it.

Note: Using the --color option may incur a noticeable performance penalty when ls is run in a directory with very many entries. The default settings require ls to stat(1) every single file it lists. However, if you would like most of the file-type coloring but can live without the other coloring options (e.g. executable, orphan, sticky, other-writable, capability), use dircolors to set the LS_COLORS environment variable like this:

eval $(dircolors -p | perl -pe 's/^((CAP|S[ET]|O[TR]|M|E)\w+).*/$1 00/' | dircolors -)

See ls(1) for more information.

1.5 man

To enable colored man, two main pagers, less and most, are hacked here.

1.5.1 Using less

See #less for a more detailed description.

For bash or zsh, add the following less wrapper function to ~/.bashrc or ~/.zshrc:

man() {
    LESS_TERMCAP_md=$'\e[01;31m' \
    LESS_TERMCAP_me=$'\e[0m' \
    LESS_TERMCAP_se=$'\e[0m' \
    LESS_TERMCAP_so=$'\e[01;44;33m' \
    LESS_TERMCAP_ue=$'\e[0m' \
    LESS_TERMCAP_us=$'\e[01;32m' \
    command man "$@"
}

For Fish you could accomplish this with:

~/.config/fish/config.fish

set -xU LESS_TERMCAP_md (printf "\e[01;31m")
set -xU LESS_TERMCAP_me (printf "\e[0m")
set -xU LESS_TERMCAP_se (printf "\e[0m")
set -xU LESS_TERMCAP_so (printf "\e[01;44;33m")
set -xU LESS_TERMCAP_ue (printf "\e[0m")
set -xU LESS_TERMCAP_us (printf "\e[01;32m")

Remember to source your config or restart your shell to make the changes take effect.

1.5.2 Using most

The basic function of 'most' is similar to less and more, but it has a smaller feature set. Configuring most to use colors is easier than using less, but additional configuration is necessary to make most behave like less. Install the most package.

Edit /etc/man_db.conf, uncomment the pager definition and change it to:

DEFINE     pager     most -s

Test the new setup by typing:

$ man whatever_man_page

Modifying the color values requires editing ~/.mostrc (creating the file if it is not present) or editing /etc/most.conf for system-wide changes. Example ~/.mostrc:

% Color settings
color normal lightgray black
color status yellow blue
color underline yellow black
color overstrike brightblue black

Another example showing keybindings similar to less (jump to line is set to 'J'):

% less-like keybindings
unsetkey "^K"
unsetkey "g"
unsetkey "G"
unsetkey ":"

setkey next_file ":n"
setkey find_file ":e"
setkey next_file ":p"
setkey toggle_options ":o"
setkey toggle_case ":c"
setkey delete_file ":d"
setkey exit ":q"

setkey bob "g"
setkey eob "G"
setkey down "e"
setkey down "E"
setkey down "j"
setkey down "^N"
setkey up "y"
setkey up "^Y"
setkey up "k"
setkey up "^P"
setkey up "^K"
setkey page_down "f"
setkey page_down "^F"
setkey page_up "b"
setkey page_up "^B"
setkey other_window "z"
setkey other_window "w"
setkey search_backward "?"
setkey bob "p"
setkey goto_mark "'"
setkey find_file "E"
setkey edit "v"

1.5.3 Using X resources

A quick way to add color to manual pages viewed on xterm/uxterm or rxvt-unicode is to modify ~/.Xresources.

1.5.3.1 xterm

*VT100.colorBDMode:     true
*VT100.colorBD:         red
*VT100.colorULMode:     true
*VT100.colorUL:         cyan

which replaces the decorations with the colors. Also add:

*VT100.veryBoldColors: 6

if you want colors and decorations (bold or underline) at the same time. See xterm(1) for a description of the veryBoldColors resource.

1.5.3.2 rxvt-unicode

URxvt.colorIT:      #87af5f
URxvt.colorBD:      #d7d7d7
URxvt.colorUL:      #87afd7

Run:

$ xrdb -load ~/.Xresources

Launch a new xterm/uxterm or rxvt-unicode and you should see colorful man pages.

This combination puts colors to bold and underlined words in xterm/uxterm or to bold, underlined, and italicized text in rxvt-unicode. You can play with different combinations of these attributes (see the sources Template:Dead link of this item).

1.6 pacman

Pacman has a color option. Uncomment the Color line in /etc/pacman.conf.

2 Wrappers

Template:Move

2.1 Universal wrappers

(most of them outdated but still functioning)

They go with multiple preconfigured presets that can be changed, and new can be created/contributed.

grc — Yet another colouriser for beautifying your logfiles or output of commands.
Presets: configure, cvs, df, diff, esperanto, gcc, irclog, ldap, log, mount, netstat, ping, proftpd, traceroute, wdiff.

https://github.com/pengwynn/grc || grc

colorlogs — Colorize commands output or STDIN using patterns.
Presets: logs, git status, ant, maven.

https://github.com/memorius/colorlogs || {{{4}}}

cw — A non-intrusive real-time ANSI color wrapper for common unix-based commands.
Presets: arp, arping, auth.log@, blockdev, cal, cksum, clock, configure, cpuinfo@, crontab@, cw-pipe, cw-test.cgi, date, df, diff, dig, dmesg, du, env, figlet, file, find, finger, free, fstab@, fuser, g++, gcc, group@, groups, hdparm, hexdump, host, hosts@, id, ifconfig, inittab@, iptables, last, lastlog, lsattr, lsmod, lsof, ltrace-color, make, md5sum, meminfo@, messages@, mount, mpg123, netstat, nfsstat, nmap, nslookup, objdump, passwd@, ping, pmap, pmap_dump, praliases, profile@, protocols@, ps, pstree, quota, quotastats, resolv.conf@, route, routel, sdiff, services@, showmount, smbstatus, stat, strace-color, sysctl, syslog, tar, tcpdump, tracepath, traceroute, umount, uname, uptime, users, vmstat, w, wc, whereis, who, xferlog.

http://cwrapper.sourceforge.net/ || cw

ccze — A fast log colorizer written in C, intended to be adrop-in replacement for colorize

https://github.com/cornet/ccze/ || ccze

2.2 Libraries for colorizing an output

ruby-rainbow — Rainbow is extension to ruby's String class adding support for colorizing text on ANSI terminal

https://rubygems.org/gems/rainbow/ || ruby-rainbow

python-blessings — A thin, practical wrapper around terminal coloring, styling, and positioning

https://pypi.python.org/pypi/blessings || python-blessings, python2-blessings

2.3 Application specific

2.3.1 Compilers

colorgcc — A Perl wrapper to colorize the output of compilers with warning/error messages matching the gcc output format

https://schlueters.de/colorgcc.html || colorgcc

2.3.2 diff

Diff has built-in color output, which is reasonable to use. But the following wrapper can be used:

colordiff — Perl script for diff highlighting.

http://www.colordiff.org/ || colordiff

2.3.3 less

2.3.3.1 source-highlight

You can enable code syntax coloring in less. First, install source-highlight, then add these lines to your shell configuration file:

~/.bashrc

export LESSOPEN="| /usr/bin/source-highlight-esc.sh %s"
export LESS='-R '

2.3.3.2 lesspipe

Frequent users of the command line interface might want to install lesspipe.

Users may now list the compressed files inside of an archive using their pager:

$ less compressed_file.tar.gz

==> use tar_file:contained_file to view a file in the archive
-rw------- username/group  695 2008-01-04 19:24 compressed_file/content1
-rw------- username/group   43 2007-11-07 11:17 compressed_file/content2
compressed_file.tar.gz (END)

lesspipe also grants less the ability of interfacing with files other than archives, serving as an alternative for the specific command associated for that file-type (such as viewing HTML via python-html2text).

Re-login after installing lesspipe in order to activate it, or source /etc/profile.d/lesspipe.sh.

2.3.4 Ping

prettyping — Add some great features to ping monitoring. A wrapper around the standard ping tool with the objective of making the output prettier, more colorful, more compact, and easier to read.

http://denilson.sa.nom.br/prettyping/ || prettyping

3 Shells

4 Terminal emulators

4.1 Virtual console

Template:Style

The colors in the Linux virtual console running on the framebuffer can be changed. This is done by writing the escape code \\e]PXRRGGBB, where X is the hexadecimal index of the color from 0-F, and RRGGBB is a traditional hexadecimal RGB code.

For example, to reuse existing colors defined in ~/.Xresources, add the following to the shell initialization file (such as ~/.bashrc):

if [ "$TERM" = "linux" ]; then
    _SEDCMD='s/.*\*color\([0-9]\{1,\}\).*#\([0-9a-fA-F]\{6\}\).*/\1 \2/p'
    for i in $(sed -n "$_SEDCMD" $HOME/.Xresources | awk '$1 < 16 {printf "\\e]P%X%s", $1, $2}'); do
        echo -en "$i"
    done
    clear
fi

4.1.1 Login screen

The below is a colored example of the virtual console login screen in /etc/issue. Create a backup of the original file with mv /etc/issue /etc/issue.bak as root, and create a new /etc/issue:

\e[H\e[2J
                                                            \e[1;30m| \e[34m\\s \\r
       \e[36;1m/\\\\                      \e[37m||     \e[36m| |                   \e[30m|
      \e[36m/  \\\\                     \e[37m||     \e[36m|     _               \e[30m| \e[32m\\t
     \e[1;36m/ \e[0;36m.. \e[1m\\\\   \e[37m//==\\\\\\\\ ||/= /==\\\\ ||/=\\\\  \e[36m| | |/ \\\\ |  | \\\\ /     \e[30m| \e[32m\\d
    \e[0;36m/ .  . \\\\  \e[37m||  || ||   |    ||  || \e[36m| | |  | |  |  X      \e[1;30m|
   \e[0;36m/  .  .  \\\\ \e[37m\\\\\\\\==/| ||   \\\\==/ ||  || \e[36m| | |  | \\\\_/| / \\\\     \e[1;30m| \e[31m\\U
  \e[0;36m/ ..    .. \\\\   \e[0;37mA simple, lightweight linux distribution.  \e[1;30m|
 \e[0;36m/_\x27        `_\\\\                                             \e[1;30m| \e[35m\\l \e[0mon \e[1;33m\\n
 \e[0m

Save the file and make it executable with chmod +x /etc/issue.

4.2 X window system

Most Xorg terminals, including xterm and urxvt, support at least 16 basic colors. The colors 0-7 are the 'normal' colors. Colors 8-15 are their 'bright' counterparts, used for highlighting. These colors can be modified through X resources, or through specific terminal settings. For example:

~/.Xresources

! Black + DarkGrey
*color0:  #000000
*color8:  #555753
! DarkRed + Red
*color1:  #ff6565
*color9:  #ff8d8d
! DarkGreen + Green
*color2:  #93d44f
*color10: #c8e7a8
! DarkYellow + Yellow
*color3:  #eab93d
*color11: #ffc123
! DarkBlue + Blue
*color4:  #204a87
*color12: #3465a4
! DarkMagenta + Magenta
*color5:  #ce5c00
*color13: #f57900
!DarkCyan + Cyan (both not tango)
*color6:  #89b6e2
*color14: #46a4ff
! LightGrey + White
*color7:  #cccccc
*color15: #ffffff

Warning: Color resources such as foreground and background can be read by other applications (such as emacs). This can be avoided by specifiying the class name, for example XTerm.foreground.

4.3 Display all 256 colors

Prints all 256 colors across the screen.

$ (x=`tput op` y=`printf %76s`;for i in {0..256};do o=00$i;echo -e ${o:${#o}-3:3} `tput setaf $i;tput setab $i`${y// /=}$x;done)

4.4 Display tput escape codes

This article is a candidate for merging.

It is suggested that this page or section be merged with Bash/Prompt_customization. (Discuss)

Replace tput op with whatever tput you want to trace. op is the default foreground and background color.

$ ( strace -s5000 -e write tput op 2>&2 2>&1 ) | tee -a /dev/stderr | grep -o '"[^"]*"'

033[\033[1;34m"\33[39;49m"\033[00m

4.5 Enumerate supported colors

The following command will let you discover all the terminals you have terminfo support for, and the number of colors each terminal supports. The possible values are: 8, 15, 16, 52, 64, 88 and 256.

$ for T in `find /usr/share/terminfo -type f -printf '%f '`;do echo "$T `tput -T $T colors`";done|sort -nk2

Eterm-88color 88
rxvt-88color 88
xterm+88color 88
xterm-88color 88
Eterm-256color 256
gnome-256color 256
konsole-256color 256
putty-256color 256
rxvt-256color 256
screen-256color 256
screen-256color-bce 256
screen-256color-bce-s 256
screen-256color-s 256
xterm+256color 256
xterm-256color 256

4.6 Enumerate terminal capabilities